You can do that right now in every modern socialist country, but what about the USSR and the Warsaw Pact? And any future socialist and communist experiment(s)?
By self-employment, I'm indeed referring to running your own business, but I'm referring to a sole proprietorship or freelancing, not your typical business where other workers are exploited for the benefit of the owner.
no. A socialist country which allows people to put up own businesses would have some kind of "free-market" where you can open a Pizzeria and have to compete with the guy next block who also happens to have opened a Pizzeria. Under such society competition would arise between the self-employed where someones Pizzeria would win the competition by making cheaper Pizza or whatever and therefore gain more customers (customers which the competitors Pizzeria would loose which then again lead to the competitor eventually loosing his shop) We would see the problems of capitalist society or at least some aspects of these rise up in such a scenario.